Banca de QUALIFICAÇÃO: FELIPE PORTO FIUZA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : FELIPE PORTO FIUZA
DATA : 20/06/2017
HORA: 14:00
LOCAL: Anfiteatro das Aves
TÍTULO:

Investigation of aging effects in morphological quantitative parameters and immunoreactivity of Calcium binding proteins in the rat lateral geniculate nucleus

PALAVRAS-CHAVES:

Aging, Lateral geniculate nucleus, Stereology, Zeitgeber Time, Calretinin, Calbindin.

PÁGINAS: 50
GRANDE ÁREA: Ciências Humanas
ÁREA: Psicologia
RESUMO:

Normal aging is accompanied by declines in visual system even in the absence of pathological processes. Among the components of this system, the lateral geniculate nucleus (LGN) offers a good model for aging studies, since it comprises three nuclei, namely dorsal Lateral Geniculate Nucleus (dLGN), intergeniculate leaflet (IGL) and ventral lateral geniculate nucleus (vLGN),  involved in distinct functional aspects of image forming and non-image forming systems. A characteristic of these nuclei is the immunoreactivity of calcium binding proteins (CaBPs), which regulates the intracellular concentration of this íon. In parallel, modern theories of aging correlates functional deficits of neurons to dysregulation of calcium homeostatic mechanisms, bringing research interest in CaBPs.  In this field, the majority of investigations are performed in restrict periods of day despite the fact those proteins have daily variations of immunoreactivity expression. In this context, the present study aims to describe quantitative morphological parameters of LGN and immunoreactivity of the CaBPs calretinin (CR) and calbindin (CB) in distinct periods of day across different age groups. Male wistar rats were divided in three age groups: young, middle-age and aged (3, 13 and 23 months old) and perfused with formalin (10%) in Zeitgeber times (ZTs) corresponding to distinct photic conditions. Then the brains were sectioned and submitted to immunohistochemistry for Neuronal Nuclei protein (NeuN) with Nissl counterstain or immunohistochemistry for CR or CB. The sections were analyzed by the stereological methodologies of optical fractionator and Cavalieri estimator. Until the present moment, we describe the neuronal and glial numbers, glia/neuron ratio and volume of LGN nuclei, as well as CR immunoreactivity of IGL in distinct ZTs. We observed LGN neuronal numbers remained stable in the course of aging. However, glial numbers, glia/neuron ratio and volume increased in a region-specific manner. These data might reflect a compensatory mechanism in response to a chronic neuroinflammatory environment. In addition, we observed a peak of CR-immunorreactive cells in IGL at transition of light to dark period in young and middle-aged animals, but not in aged ones. Furthermore, in the dark period we found a 26% reduction of CR expressing cells in aged animals in comparison with young ones. Based on our data, we suggest that despite the CR immunoreactivity remains stable in light periods, it suffers a progressive loss in the dark phase during aging, which can be detected in middle-age group and becomes evident in aged animals.

MEMBROS DA BANCA:
Externo ao Programa - 1076490 - FERNANDO VAGNER LOBO LADD
Presidente - 2351800 - JEFERSON DE SOUZA CAVALCANTE
Externo ao Programa - 3492786 - RUTHNALDO RODRIGUES MELO DE LIMA